Scala rocks! It is statically typed, has functional features, and aims for developer productivity. In Scala you can express what you want with less code than in C#. Scala runs on JVM and any Java code can be called from Scala.

Actors - a totally different thinking about concurrency than you are used to. No threads + shared state + locks. Actors live independently, share no state, and communicate by sending each other messages.

Adding new keywords to the language just by writing ordinary methods. Consider adding C#'s using or lock keyword to Scala, without compiler support!

Traits - behaviors can be mixed in freely at instatiation time, sort of built-in Strategy design pattern.

Absence of the static keyword, turns out it is not needed! Instead of having static state and methods of a class, you declare a singleton instance and call its methods.

If you want to see concrete examples, check out the slides.. it's coding time ;)